Mrs Brown denied her husband would be “difficult to live with” if he was not Labour leader or Prime Minister.

She said: “No I think Gordon is always going to be someone who is engaged in doing what he thinks he can do that will make a difference to people.

“That has been the Gordon I have known and the Gordon I have heard about all his life. From when he was a kid selling a newspaper to raise money for the Oxfam campaign of the day. That is Gordon, that is the person that he is.”

The Browns were speaking ahead of a 36 hour election tour which will take them across the country in a final push before election day.

One of the themes of the last hours of campaigning will be the party’s commitment to tax credits, which suggests Labour is trying to shore up its core vote to avoid a heavy defeat.

Mr Brown said: “Six million families get these tax credits. Lots of people depend on them for what they can do for their children.

“Now the Liberals and Conservatives want to take away child tax credits from large numbers of children. I have never seen so many undecided.

“The people are the boss. I don’t want to be arrogant and assume what they say. Once they have made their views we will act upon it.”

Mrs Brown said she was enjoying getting “stuck in with the campaign. I wanted to get out there and meet people”.

Asked if she was protective of her husband on the campaign trail, she said: “We are out and about together. I don’t want to get left behind from him.

“He is a tough, engaged, passionate and really engaged in everything he is doing.”